Papers by Keyword: FLD

Abstract: This article presents a comprehensive study on the damping of vibrations in a motor-pump assembly using viscoelastic and constrained layer damping treatments. The assembly's structural model, designed using SolidWorks software, is subjected to modal and harmonic analyses in ANSYS. The primary goal is to mitigate vibration amplitudes originating from the motor and pump to enhance the assembly's operational performance. Three damping treatments are investigated: Free Layer Damping (FLD), Sandwich Constrained Layer Damping (CLD), and a novel Multilayer CLD approach. The viscoelastic material is modeled using the Prony series method, and its properties are incorporated into the finite element analysis Results demonstrate that the application of damping treatments significantly reduces vibration amplitudes compared to the untreated structure. Among the treatments, the Multilayer CLD approach exhibits the highest damping efficiency, reducing the maximum amplitude by approximately 52% compared to the base structure. The study showcases the advantages of utilizing viscoelastic and constrained layer damping techniques for enhancing vibration control and operational stability in industrial assemblies. The research findings contribute to the field of structural dynamics and vibration control, offering valuable insights into the design and optimization of mechanical systems subjected to dynamic loads. This study opens avenues for further research and practical applications aimed at improving the performance and reliability of motor-pump assemblies and similar industrial equipment.

Abstract: Forming Limit Diagram (FLD) is a resourceful tool to study the formability of sheet metals. Research on the formability of Perforated Sheet Metal is growing over the years as perforated sheet metal finds its applications in various fields. But finding FLD of perforated sheet metals is complex due to the presence of holes. Also, the hole size, shape and pattern, ligament ratio, thickness of the blank, percentage of open area influence the formability of a perforated sheet metal.In the present scenario, various simulation softwares have made the process of plotting FLD much easier, saving time and money. This paper is an attempt to predict the formability of mild steel perforated sheet metal through simulation software package LS Dyna. Also, Parametric analysis is performed to determine the influence of geometric parameters on the drawability of the perforated sheet metal.

Abstract: As the study of formability of perforated sheet metals using conventional approach is exhaustive and time consuming, Finite Element Analysis is used to carry out the same. This paper attempts to study the effects of perforation parameters (viz. hole size, open area and thickness) on the formability of square hole Perforated Mild Steel Sheet Metal. Finite element analysis is done using commercial Finite Element Analysis software LS-DYNA. Parametric analysis is carried out to optimize process parameters using Taguchi’s L9 orthogonal array. From the results obtained through simulation, the analysis of variance (ANOVA) is carried out to determine which group has best condition for drawing and regression equation is obtained to know, how a single response variable (Major or Minor strain) is related to a variety of predictor variables (percentage open area, hole size and thickness) and the graphs are plotted between them using MINITAB software.

Abstract: The paper presents a methodology developed by the author for reconstructing surfaces of shaping the punch which is an element of the stamping die. It describes the entire process of the punch reconstruction i.e. 3D scanning, modeling, FEM analysis and processing. This process was implemented by the stamping press cooperating with the authors. Conclusions have been formulated.

Abstract: Strain paths during sheet metal forming are always complex and nonlinear. Forming limit diagram (FLD) is a common method to determine failure in the past decades. However, it is only suitable for linear strain path condition. Regarding dual phase steel DP780, a special experiment was designed and carried out on Zwick Cupping equipment to get nonlinear strain paths. And the strain status was analyzed in FLD. It was found that FLD cannot predict failure precisely in this case. A new approach proposed by Stoughton and Yoon which based on polar effective plastic strain was introduced to analyze this nonlinear strain paths condition, the result is in good agreement with experiment, which indicated that Polar Effective Plastic Strain Diagram was an effective and precise tool to determine failure especially for complex nonlinear strain paths forming.

Abstract: This paper presents the influence of modeling and simulation techniques for hard milling and forming. The aim of these simulations is the ability to optimize the manufacturing technologies even before the real production of its own tools, because their manufacturing process is very difficult in terms of production time, materials and other costs. The simulated results visualize roughing and finishing process of milling and generate tool-paths in CATIA V5. Simulation results of forming realized in PAM-Stamp 2G using a 3D model of the punch and the blank confirm the suitability of the proposed design of the forming tool. Finally, hard milling and forming simulations in CAE systems CATIA V5 and PAM-Stamp 2G were performed in order to determine and evaluation of suitability of the proposed shapes of the forming tool.

Abstract: Optical strain analysis system plays an important role in tools and dies design, particularly in the phase of die design and die tryout. The objective of this paper is to present the information of the application by using the optical strain measurement device in tools and dies design and material testing. Therefore, two cases in mechanical testing and one case of tools and dies design are demonstrated. The AutoGrid^® Compact strain measuring device is applied for all cases. The determination of Forming Limit Diagram (FLD) by using tensile testing machine and U-bending test supported by the optical strain measuring technique is performed and illustrated. In this paper, the procedure of material testing is developed and applied from related literatures. The result obtained from several cases shows the powerful performance of using the strain measurement device for providing the strain information in each situation of forming material as required so that the engineer can tackle the problem and find the solution to improve the production processes in a short time.

Abstract: QP steel has great application potential for automotive industry for its ultrahigh strength and good plasticity. In this paper, the forming limit diagram (FLD) of QP steel was experimentally studied using spherical punch test. The forming limit curves (FLC) of QP steel in room temperature under two pressing velocities (20mm/s, 2mm/s) were obtained. It has been found that the deformation velocity affects the FLC obviously; the FLC declines with the increase of pressing velocity. Compared with other AHSS under the same strength grade, QP steel keeps high strength without a significant loss of plasticity.

Abstract: Forming limit strains are used to construct a forming limit diagram (FLD), which is a diagram in the principal strain space, traditionally used for designing forming operations of sheet metals. A line indicating the boundary between safe and unsafe strains is often called the forming limit curve (FLC). FLDs are also used to evaluate results from finite element simulations. Therefore consistency and reproducibility are important. This paper deals with the experimental determination of forming limit strains from Marciniak-Kuczynski (MK) tests. The material tested is AA6016 aluminum alloy in three different conditions: virgin material and material subjected to 5% and 8% deformation by rolling. Strains were measured by the use of digital image correlation (DIC) technique. Forming limit strains were determined by the use of two automated methods. The results from the two methods are compared and evaluated regarding their applicability to the Marciniak-Kuczynski test and ability to capture actual forming limit strains.

Abstract: In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.